The present invention relates to a control unit for xe2x80x9cpilgrim stepxe2x80x9d operation of the detaching cylinders of a combing machine.
As is known, combing machines are used to comb natural textile fibres; this operation consists in positioning the fibres in a parallel direction, to make them suitable for subsequent spinning treatments.
To perform this combing operation of the textile fibres, known combing machines are provided with a plurality of components that act on the textile fibres and operate in synchronism.
In particular, combing is performed by means of a circular comb with a toothed sector to penetrate between the fibre cloth tufts, so that the teeth of the toothed sector remove the short fibres.
Moreover, a group of detaching cylinders moves the combed fibre tuft forwards and backwards, according to a movement commonly known as xe2x80x9cpilgrim stepxe2x80x9d, in synchronism with the movement of the circular comb.
Examples of such combing machines are described in the patents No. MI 22135A/87 and No. EP 0 374 723.
In the first of these known systems, a cam, provided with uniform rotary motion, engages with contrast rollers that provide alternate movement to a connecting rod, the latter being joined to an end of a forked arm, mounted on a shaft entering a differential.
Splined on this shaft is a toothed wheel or planetary gear that engages another three input planet wheels, in turn connected to output planet wheels that engage an output planetary gear, flanged on which is a gear.
This gear meshes with a pair of spools, fitted at the ends of respective spindles, provided with a splined portion, and realising the detaching cylinders.
By means of this combination of components, alternate movement of the connecting rod is transmitted to the detaching cylinders to perform xe2x80x9cpilgrim stepxe2x80x9d movement of these.
Nonetheless, in this system, there are components to transmit motion to the detaching cylinders, such as the connecting rod, provided with alternate movement, which must thus be started, stopped and made to start up again in the opposite direction, which is somewhat wasteful from the point of view of energy and also the source of undesired excessive stress on the machine.
A second known system is described in the patent No. EP 0 374 723.
According to this solution, xe2x80x9cpilgrim stepxe2x80x9d movement of the detaching cylinders is obtained using an electric motor, in particular a brushless motor, to operate the detaching cylinders by means of suitable reduction components.
The electric motor is fed with electrical impulses synchronised with the rotary movement of the circular combs; moreover, the electric motor is reversible, so that the detaching cylinders can rotate both forwards and backwards.
Although devices of this second type are able to perform the function for which they have been designed, they have the shortcoming that the motors to operate the detaching cylinders must be stopped and started up again.
Therefore, the object of the present invention is to create a control unit for operation of detaching cylinders in a combing machine that allows the above problems to be solved, permitting efficient operation of the combing machine.
Another object of the present invention is to create a control unit for operation of the detaching cylinders that allows better operating characteristics and greater overall efficiency of the combing machine to be obtained, together with decreased wear through time, owing to reduced stress.
Yet another object of the present invention is to present a control unit for operation of detaching cylinders that can be set at work in a simple and inexpensive manner, without the need to use costly materials or complex technologies.
These and other objects are achieved with a control unit for xe2x80x9cpilgrim stepxe2x80x9d operation of the attaching cylinders in a combining machine, having a control unit (10), for xe2x80x9cpilgrim stepxe2x80x9d operation of a plurality of detaching cylinders (22,23) in a combing machine, comprising a first electric motor (1), which rotates with uniform motion components of the aforesaid combing machine by way of a shaft (17) and a second electric motor (11), which rotates a shaft (12), said shaft (12) housing components to transmit motion to said detaching cylinders (22, 23), said first electric motor (1) also acts on components of a control unit (10) to transmit motion to said detaching cylinders (22, 23), and said second motor (11) is provided with means of operation with a unidirectional law of motion comprising acceleration and deceleration phases, where both said first and second motors are connected by tooth gears (15, 16) at all times and always rotate continuously in one direction and their rotary motions are combined by means of a differential device to obtain resulting motion of the xe2x80x9cpilgrim stepxe2x80x9d type on said detaching cylinders (22, 23).
Further characteristics of the present invention are defined, moreover, in the subsequent claims.